This invention relates to equalization methods and circuits for data communication. Methods and circuits are presented that improve the quality of equalization for input signals with varying amplitudes.
Equalization circuits are used to process received signals to improve the quality of the received signals. Equalization circuits compensate for the attenuation, delay and distortion suffered by the received signal during transmission. In some applications such as high-speed communications, high quality equalization is required in order to support high-speed and high-accuracy transmission of data signals. In order to increase the quality of equalization, equalization circuits may be designed to compensate for the particular characteristics of the attenuation, delay, and distortion caused by the combination of transmitter circuitry, transmission link, and receiver circuitry used. Equalization circuits may also be optimized to function with particular transmission protocols.
In applications in which equalization circuits may be used with various transmitter circuits, transmission links, receiver circuits, and/or transmission protocols, it may not be possible to design the equalization circuits to provide optimal signal equalization for use with all combinations of circuits and links. Adjustable equalization circuits may be used in such situations, and may allow users to adjust the characteristics of the equalizer to provide improved signal equalization. However, the use of adjustable equalization circuits may require complex and time consuming equalization adjustment procedures prior to signal transmission. In addition, the adjustment process may need to be repeated if characteristics of the transmission attenuation, delay, or distortion change. Adjustable equalization circuits may therefore not be well suited for use in certain situations.
Methods and circuits for automatic adjustment of equalization may provide optimized signal equalization despite changes in transmitter, transmission link and receiver distortion. Automatic adjustment of equalization may additionally provide dynamic equalization adjustment to compensate for changes in distortion occurring during signal transmission.